Neural stimulation and optical monitoring systems and methods

ABSTRACT

Neural stimulation and optical monitoring systems and methods are disclosed. In one embodiment, an apparatus for treating a neural condition includes a signal delivery device configured to be implanted into a patient proximate to a skull of the patient and positioned to apply electromagnetic signals to one or more target sites within the patient. The apparatus also includes an implantable optical monitoring assembly configured to monitor optical properties at one or more optical monitoring sites within the patient. The apparatus further includes a controller configured to be implanted into the patient. The controller is operatively coupled to the signal delivery device and the optical monitoring assembly and programmed to control both the signal delivery device and the optical monitoring assembly. The controller also includes a power source to power both the signal delivery device and the optical monitoring assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of prior U.S. application Ser. No.11/583,349, filed Oct. 18, 2006, pending which claims the benefit ofU.S. Provisional Application No. 60/728,650, filed Oct. 19, 2005, whichis incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to the use of opticalmonitoring techniques in association with providing neural stimulationto particular target neural populations. More particularly, the presentdisclosure describes various embodiments of optical monitoring systems,devices, and/or elements that may be used in association with particularneural stimulation systems, devices, and/or elements.

BACKGROUND

A wide variety of mental and physical processes are controlled orinfluenced by neural activity in particular regions of the brain. Forexample, the neural functions in some areas of the brain (i.e., thesensory or motor cortices) are organized according to physical orcognitive functions. In general, particular areas of the brain appear tohave distinct functions in most individuals. In the majority of people,for example, the areas of the occipital lobes relate to vision, theregions of the left interior frontal lobes relate to language, and theregions of the cerebral cortex appear to be consistently involved withconscious awareness, memory, and intellect.

Many problems or abnormalities with body functions can be caused bydysfunction, damage, disease and/or disorders in the brain. Effectivelytreating such abnormalities may be very difficult. Epidemiologicalprofiles indicate that the treatment and/or rehabilitation of neurologicdysfunction is extremely challenging due to patient populationheterogeneity, for example, due to factors such as age, gender,ethnicity, cause, physiologic location, severity, and time since onset.For most patients exhibiting neurologic damage arising from, forexample, a stroke, conventional treatments are not sufficient, andlittle can be done to significantly improve the function of an affectedbody part or cognitive function beyond the limited recovery thatgenerally occurs naturally without intervention.

Optical monitoring may facilitate the evaluation of various types oftissue conditions and/or properties, for example, through near infraredspectroscopy (NIRS). A need exists for neural stimulation systems andmethods that include or incorporate particular optical monitoringtechniques.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a neural stimulation and opticalmonitoring system configured in accordance with an embodiment of theinvention.

FIG. 2 is a schematic illustration of a neural stimulation and opticalmonitoring system configured in accordance with another embodiment ofthe invention.

FIG. 3 is a schematic illustration of a neural stimulation and opticalmonitoring system configured in accordance with still another embodimentof the invention.

FIG. 4 is a schematic illustration of an implantable stimulation andoptical controller that may be coupled to an electrode assembly, anoptical monitoring assembly, and/or a stimulation and optical monitoringassembly according to an embodiment of the invention.

FIG. 5 is a schematic illustration of an optical monitoring assemblyconfigured in accordance with an embodiment of the invention.

FIG. 6A is a schematic illustration of a stimulation and opticalmonitoring assembly configured in accordance with an embodiment of theinvention.

FIG. 6B is a schematic illustration of a stimulation and opticalmonitoring assembly configured in accordance with still anotherembodiment of the invention.

FIG. 7 is a flow diagram illustrating a process for applying neuralstimulation in accordance with an embodiment of the invention.

DETAILED DESCRIPTION A. Introduction

The following disclosure describes various embodiments of neuralstimulation and optical monitoring (NSOM) systems. Different types oftissues or substances may absorb, transmit, scatter, reflect, and/oremit optical signals in different manners based upon the opticalresponse characteristics of such tissue or substances. For example,optical signals may be used to detect, monitor, estimate, or measurechanges in hemodynamic properties (e.g., fluctuations in oxy-hemoglobinor deoxy-hemoglobin levels, blood volume, or blood flow) and/or othertissue properties, typically in a selective manner. Irradiation oftissues or substances with optical signals having particularcharacteristics (e.g., single or multiple wavelengths, and/or coherentlight) may facilitate the detection, identification, or measurement ofspecific types of biological information. Systems and methods inaccordance with various embodiments of the invention may comprisedevices configured for near infrared spectroscopy (NIRS), opticaltomography (OT), laser Doppler flowmetry, fluorescence spectroscopy,and/or other optical techniques.

Depending upon embodiment details, systems in accordance with variousembodiments of the present invention may comprise one or more types ofneural stimulation devices and/or signal transfer elements configured toapply neural stimulation signals to a set of stimulation sites; and oneor more types of optical signal sources, optical signal detectors, andoptical signal transfer elements configured to monitor or measureoptical signals and/or signal properties at a set of optical monitoringsites.

Some embodiments may apply or deliver particular types of neuralstimulation and/or chemical substances to a patient in association withoptical monitoring. A neural stimulation and/or chemical delivery andoptical monitoring system (NSCDOMS) may comprise a set of neuralstimulation devices configured to provide stimulation signals to a setof stimulation sites; one or more chemical substance infusion ordelivery devices (e.g., an implantable drug infusion pump) configured torelease or apply one or more chemical substances (e.g., an amphetamine,a pharmacologic agent, a neuroprotective agent, neurotrophic agent, agrowth factor, a muscle relaxant, or another substance) to a set ofdelivery sites upon or within a patient's body; and a set of opticalsignal sources, detectors, and other optical elements (e.g., opticalfibers).

Particular system embodiments may also include other types of monitoringsystems and/or devices for monitoring or measuring patient state signalsand/or patient responses, as further described below. Various systemembodiments may further comprise hardware and/or software for processingor analyzing neural stimulation, chemical, optical, and/or other typesof signals.

Systems and methods in accordance with various embodiments of theinvention may be directed toward restoring, developing, and/or enhancingparticular types of neural function, and/or treating or amelioratingneurologic dysfunction. Neurologic dysfunction may include disorders,diseases, injuries, and/or abnormalities related to brain and/or otherneural tissue functions. Representative types of neurologic dysfunctionmay correspond to stroke, traumatic brain injury (TBI), a maladaptiveneuroplastic condition, a pain syndrome, auditory disorders (e.g.,tinnitus or auditory hallucinations), speech or language disorders(e.g., aphasia), learning disorders (e.g., dyslexia), Parkinson'sDisease, essential tremor, and/or one or more other disorders, states orconditions.

Optical monitoring may facilitate the determination of (1) one or moreneural stimulation and/or chemical substance delivery sites; (2) levels(e.g., a peak amplitude), ranges, and/or other characteristics (e.g., apulse repetition frequency or a modulation pattern) of particular neuralstimulation and/or chemical substance delivery parameters; (3) whetherneural stimulation and/or a chemical substance therapy is providing anintended or desirable effect; (4) whether to initiate, query, adjust,vary, interrupt, resume, or discontinue neural stimulation and/or achemical substance therapy, possibly in an adaptive manner; and/or (5) alikelihood that a patient will experience a given or target level ofneurofunctional restoration development in association with neuralstimulation and/or chemical substance therapy.

Depending upon embodiment details, neural stimulation may correspond totranscranial, cortical, subcortical, deep brain, cerebellar, spinalcolumn, cranial or other peripheral nerve, and/or other types of neuralstimulation. Representative types of neural stimulation that may beemployed in particular embodiments include one or more of corticalstimulation (CS), vagal nerve stimulation (VNS), deep brain stimulation(DBS), transcranial magnetic stimulation (TMS), and transcranial directcurrent stimulation (tDCS).

The neural stimulation, substance delivery, and/or optical monitoringmay be directed toward one or more anatomical locations. An anatomicallocation or region at which neural stimulation signals are applied ordelivered to, or through, or near a target neural population may bedefined as a stimulation site. One or more optical monitoring sites maybe external or internal to a patient, and may be essentially identicalor proximate or near a stimulation site; or distant or remote from agiven stimulation site.

A stimulation site and/or a target neural population may be identifiedand/or located in a variety of manners, for example, through one or moreprocedures involving anatomical landmark identification; structuraland/or functional anatomical imaging (e.g., Magnetic Resonance Imaging(MRI), Diffusion Tensor Imaging (DTI), functional MRI (fMRI), PositronEmission Tomography (PET), Magnetic Resonance Angiography (MRA),Near-infrared Spectroscopy (NIRS) or Optical Tomography (OT), orMagnetoencephalography (MEG)); electrophysiological signal measurement(e.g., electroencephalography (EEG) or electromyography (EMG));anatomical spectroscopy (e.g., Magnetic Resonance Spectroscopy (MRS));and/or other techniques. Representative manners of identifying a targetneural population and/or a stimulation site are given in U.S. Pat. No.7,010,351, which is incorporated herein by reference in its entirety.

A substance delivery site may correspond, for example, to a targetneural population or a target vascular structure. A delivery site may beidentified in a variety of manners, for example, through a set ofprocedures involving anatomical landmark identification and/or medicalimaging (e.g., Magnetic Resonance Angiography (MRA)). A representativetype of neural stimulation and/or chemical substance infusion systemthat may be applicable to particular embodiments of the invention isdescribed in U.S. Pat. No. 6,782,292, which is incorporated herein byreference in its entirety. Those of ordinary skill in the relevant artwill understand that in general, a substance delivery device may includea control unit, a substance reservoir, an implantable pump unit, and oneor more substance delivery elements (e.g., a catheter). The control unitmay manage the release or delivery of a substance to particular infusionsites in predetermined amounts at one or more times.

An optical monitoring site may be determined in association with theidentification of a neural stimulation site (e.g., in a manner thatcorresponds to a type of neural activity measured by fMRI), a substancedelivery site, and/or the identification of other anatomical sites ofinterest, for example, particular vascular structures and/or certaintypes of neural tissue. Such neural tissue may comprise, for example,neural populations within, proximate to, or having projectionsassociated with a lesion or an infarct penumbra; neoplastic tissue;vascular structures; and/or implanted cells (e.g., at least partiallyundifferentiated cells such as stem cells). In some embodiments, one ormore optical monitoring sites may be associated with multiple brainregions in accordance with a known or standard type of opticalmonitoring system or device configuration, which may facilitate theacquisition and analysis of optical signals corresponding to a varietyof neural functions.

In various embodiments, the neural stimulation device(s) may apply ordeliver stimulation signals to a patient, which may compriseelectromagnetic, acoustic, thermal, and/or other types of signals (e.g.,mechanical forces) capable of affecting neural function. Electromagneticstimulation signals may be defined in accordance with spatial, temporal,electrical, and/or magnetic signal parameters, properties and/orcharacteristics. Such stimulation signals may take on various forms, andmay be characterized by various waveform characteristics (e.g., signalamplitude, duration, duty cycle, polarity, pulse width, phaseinformation, pulse repetition frequency, and burst frequency). Spatial,temporal, and/or waveform parameters may be varied in one or moremanners to enhance a likelihood of providing, maintaining, or prolongingsymptomatic relief from neurologic dysfunction.

Neural stimulation signals and/or chemical substances may be applied tothe patient in association an adjunctive therapy such as a behavioraltherapy, which may comprise one or more of physical therapy; physicaland/or cognitive skills training or practice, such as training inActivities of Daily Living (ADL); intentional use of an affected bodypart; speech therapy; vision, visual, and/or spatial perceptiontraining; a reading task; a writing task; an auditory activity, forexample, a musical or rhythmic task or training; attention tasks; acognitive activity, memory task, or memory training; comprehensiontasks; and/or other therapies or activities.

Optical signals may be monitored and/or analyzed before, during, and/orafter the application of neural stimulation signals and/or chemicalsubstances to the patient. In certain embodiments, based upon particulartypes of optical signal properties and/or changes therein, theapplication of neural stimulation signals and/or chemical substances maybe initiated, queried, adjusted, interrupted, resumed, and/ordiscontinued, possibly in an adaptive or generally adaptive manner,which may occur on a real time, near-real time, or delayed basis.

B. Embodiments of Neural Stimulation and Optical Monitoring Systems andMethods for Using Such Systems

FIG. 1 is a schematic illustration of a neural stimulation and opticalmonitoring (NSOM) system 1000 according to an embodiment of theinvention. In one embodiment, the NSOM system 1000 comprises a neuralstimulation system (NSS) 100 and an external optical monitoring system200. The NSS 100 may comprise an implantable pulse generator (IPG) 110that is coupled to a set of implanted signal transfer devices, electrodeassemblies, and/or electrodes 120. The NSS 100 may also comprise one ormore types of signal or substance monitoring devices, for example, anelectrode assembly configured to monitor electrocorticographic (ECoG)signals. Depending upon embodiment details, the NSS 100 may comprisefully implanted components that are surgically placed within a patient10, as illustrated; and/or components that are partially implanted orexternal to the patient 10.

The NSS 100 may further comprise an external programming orcommunication device 130, which in some embodiments facilitatesunidirectional or bi-directional signal transfer (e.g., through magneticor RF telemetry) involving the IPG 110. Such communication may involvethe transfer of configuration information, program instructions,stimulation signal parameters, power signals, and/or data. Thecommunication device 130 may be coupled to a programming device 140(e.g., a personal digital assistant (PDA) or a handheld, laptop, ordesktop computer) by a wire-based or a wireless link 135.

An optical monitoring system 200 may comprise a system for applyingoptical signals to and detecting optical signals scattered within orreflected by living tissue. Such a system may involve near infraredspectroscopy or optical topography. In one embodiment, the opticalmonitoring system 200 comprises at least one optical source/detectorpair 210 carried by a monitoring structure 220; and a control/analysisunit 250. Some embodiments may comprise multiple source/detector pairs210 carried by a single or multiple monitoring structures 220. Incertain embodiments the optical monitoring system 200 may be configuredfor wireless or wire-based signal transfer with the programming device140; or the communication device 130 may be coupled to the opticalmonitoring system 200 in an embodiment that omits the programming device140. In a representative embodiment, the optical monitoring system 200comprises an Imagent™ functional brain imaging system and/or anOxiplexTS™ tissue oximeter, both of which are commercially availablefrom ISS, Inc., of Champaign, Ill.

FIG. 2 is a schematic illustration of an NSOM system 1010 according toan embodiment of the invention. In one embodiment, the NSOM system 1010comprises an IPG 110; a set of electrode assembles or electrode devices120 configured to receive and apply neural stimulation signals; acommunication device 120; an optical monitoring assembly 310; and anoptical monitoring and programming device (OMPD) 300. In someembodiments, an IPG 110 may be implanted at an above-neck locationrather than at a subclavicular location as shown in FIGS. 1 and 2.

The communication device 130 may be configured for wireless signaltransfer to and/or from the IPG 110, and may be coupled to or carried bythe OPMD 300. In one embodiment, the communication device 130 is coupledto the OPMD 300 by a link 135. The optical monitoring assembly 310 maybe configured for monitoring optical signals at one or more externallocations on the patient's anatomy, and may be configured for wirelessor wire-based communication with the OPMD 300. In one embodiment, theoptical monitoring assembly 310 may be coupled to the OPMD 300 by a link315.

The optical monitoring assembly 310 may comprise a set of opticalsources, a set of optical detectors, and electrical and/or opticalsignal transfer elements, for example, in a manner described in detailby Alper Bozkurt et al. in “A portable near infrared spectroscopy systemfor bedside monitoring of newborn brain,” BioMedical Engineering Online2005, 4:29, which is incorporated herein by reference in its entirety.The optical sources and detectors may be carried by one or more supportmembers 312, which may be positioned at desired monitoring locations(e.g., upon a patient's head or scalp).

The OPMD 300 comprises a device such as a PDA or a handheld, laptop, ordesktop computer having hardware and software configured to (1) directthe generation and detection of optical signals; (2) process and/oranalyze the detected signals; (3) visually indicate (e.g., by way of adisplay device and/or a graphical user interface) detected, estimated,or measured optical signal properties and/or physiologic or physiologiccorrelate properties associated therewith; (4) direct the specificationor selection of neural stimulation parameters, which may includewaveform, spatial, and/or temporal parameters; and/or (5) communicatewith the IPG 110 to facilitate or effectuate the transfer or exchange ofneural stimulation parameters and/or other information (e.g., patientdata; or measured, sampled, or stored ECoG signals).

The optical monitoring, signal processing, and/or informationpresentation functionality of the OPMD 300 may be implemented in amanner that is essentially identical, analogous, or similar to thatdescribed by Bozkurt et al. In some embodiments, the OPMD 300 may beconfigured for wireless or wire-based communication with a computersystem 800 to facilitate certain types of signal processing, analysis,and/or characterization operations. In certain embodiments, thecommunication device 130 and the optical monitoring assembly 310 may beintegrated into or carried by a single housing or structure, which maybe handheld or adapted for wearing or carrying by the patient 10.

FIG. 3 is a schematic illustration of an NSOM system 1020 according toanother embodiment of the invention. In one embodiment, the NSOM system1020 comprises an implantable stimulation and optical monitoringcontroller (ISOMC) 400 that is coupled to a set of electrode assembliesor devices 120, a set of optical monitoring assemblies (OMAs) 460,and/or a set of stimulation and optical monitoring assemblies (SOMAs)480 by way of one or more links 435. Depending upon a type of deviceunder consideration, a link 435 may comprise one or more lead wiresand/or optical fibers to provide pathways for electrical and opticalsignals. An electrode assembly 120 may be implanted epidurally orsubdurally. Depending upon embodiment details, an OMA 460 or a SOMA 480may be implanted subcutaneously, epidurally, or subdurally.

In some embodiments, multiple OMAs 460 and/or SOMAs 480 may be implantedat or relative to different, possibly distant, brain locations. Suchbrain locations may be in the same or different brain hemispheres, suchthat noise or certain types of background activity that may affectdetected optical signal properties may be subtracted from or otherwisecompensated for relative to signals detected by particular OMAs 460and/or SOMAs 480 under consideration with respect to desired brainlocations.

Additionally or alternatively, optical signals detected in associationwith an OMA 460 and/or a SOMA 480 implanted relative to a first brainlocation may be used to (1) determine whether to apply, modify, ordiscontinue neural stimulation in a different brain area, and/or (2)select or identify one or more neural stimulation parameters inaccordance with which neural stimulation will be applied in a differentbrain area. For example, in a representative embodiment, one OMA 460 maydetect particular hemodynamic properties associated with neural activityin a healthy brain region, while another OMA 460 or a SOMA 480 detectshemodynamic properties associated with neural activity in a homologousbrain region that exhibits a type of neurologic dysfunction, forexample, a maladaptive neuroplastic condition (e.g., tinnitus or acentral pain syndrome). Based upon a difference or relationship betweendetected optical signals corresponding to such brain regions, theapplication of neural stimulation signals to the brain region exhibitingneurologic dysfunction may be initiated, continued, varied, interrupted,resumed, or discontinued.

The NSOM system 1020 further comprises a communication device 530 thatis configured for wireless or wire-based signal transfer with anexternal stimulation and optical monitoring programming device (SOMPD)500. The communication device 530 may be coupled to the SOMPD 500 by alink 535. The communication device 530 is also configured for wirelesscommunication with the ISOMC 400, such that neural stimulationparameters, optical monitoring parameters, and optical monitoringsignals or results may be communicated between the SOMPD 500 and theISOMC 400.

In various embodiments, the SOMPD 500 may (1) direct the selection ofneural stimulation and/or optical monitoring instructions, commands,and/or parameters, and their issuance to the ISOMC 400; (2) receive,process, and/or analyze signals or information received from the ISOMC400; (3) visually indicate neural stimulation information; (4) visuallyindicate detected, estimated, or measured optical signal propertiesand/or physiologic or physiologic correlate properties associatedtherewith; and/or (5) perform different or additional functions.Depending upon embodiment details, the SOMPD 500 may comprise a PDA or ahandheld or other type of computer. Particular signal processing and/orinformation presentation functionality provided by the SOPMD 500 may beimplemented in a manner that is essentially identical, analogous, orsimilar to that described above with respect to the OPMD 300.

FIG. 4 is a schematic illustration of an ISOMC 400 that may be coupledto an electrode assembly 120, an OMA 460, and/or a SOMA 480, and/orindividual light emitting and/or light detecting devices (e.g.,individual fibers or a set of fibers, which may possibly have microlens,wavelength filtering, and/or light directing elements coupled thereto)according to an embodiment of the invention. In one embodiment, theISOMC 400 comprises a power source 402, a pulse generator 410, anelectrical signal I/O unit 420, an optical signal input/output (I/O)unit 430, a signal processing unit 440, and a control and communicationunit 450. The power source 402 may comprise a battery, a capacitor,and/or another type of energy storage device. The power source 402 maybe rechargeable in certain embodiments. The pulse generator 410 maycomprise circuitry for generating and outputting neural stimulationsignals in accordance with spatial, temporal, and/or waveformparameters.

The electrical signal I/O unit 420 may comprise circuitry forinterfacing electrical signal transfer elements such as lead wires,electrical contacts or electrodes, electrode devices, and/or electrodeassemblies 120 to (1) the pulse generator 410; (2) signal storageelements, such as an electronically writable, configurable, orprogrammable medium; and/or (3) the signal processing unit 440 in amanner understood by those skilled in the art.

The optical signal I/O unit 430 may comprise one or more types of lightemitting and light detecting devices, which may include one or more of alight emitting diode (LED), a semiconductor laser, and a photodetector.The optical signal I/O unit 430 may additionally comprise one or moretypes of optical elements such as wavelength filters, beam splitters,electrical and/or optical multiplexors, and/or micromechanical opticalswitches. Additionally, the optical signals I/O unit 430 may compriseparticular types of signal modulation elements, in a manner understoodby those skilled in the art.

In various embodiments, the optical signal I/O unit 430 may includemultiple light emitting devices, each of which is configured to generatelight centered at a particular wavelength and/or having a desiredbandwidth. The optical signal I/O unit may also include multiple lightdetecting devices in a corresponding manner. Depending upon embodimentdetails, the optical signal I/O unit 430 may activate subsets of sourcesand detectors at one or more times (e.g., in a time multiplexed manner),which may facilitate power conservation. In certain embodiments, NIRSmay be facilitated by multiple infrared LEDs or semiconductor lasersoperating at optical wavelengths that may be particularly affected byhemodynamic properties. In an alternate embodiment, light emittingdevices (e.g., LEDs) may output light in the ultraviolet (UV) spectrumto facilitate fluorescence spectroscopy measurements (e.g., based uponwavelength dependent fluorescence intensity differences exhibited bydifferent tissue types, such as healthy tissue versus neoplastictissue).

One representative type of device that may be suitable for particularembodiments of the ISOMC 400 is described by Eiji Higurashi et al., in“An Integrated Laser Blood Flowmeter,” Journal of Lightwave Technology,Vol. 21, No. 3, March 2003, which is incorporated herein by reference inits entirety. Another type of device that may be suitable for particularISOMC embodiments is described by S. Shinohara et al., in “Laser Dopplervelocimeter using the self-mixing effect of a semiconductor laserdiode,” Applied Optics, Vol. 25, No. 9, p. 1417-1419, May 1986, which isincorporated herein by reference in its entirety.

The signal processing unit 440 may comprise an analog and/or digitalsignal processing device for performing operations such as signalfiltering; noise compensation; mathematical operations and/or signalanalysis associated with intensity, power, spectral, and/or phasecharacteristics of detected optical signals; and/or other operationsthat may involve generated and/or detected optical signals (e.g.,monitoring self-mixing behavior.

The control and communication unit 450 may comprise (1) a processingunit and associated circuitry for directing or managing the applicationof neural stimulation signals and the detection and processing ofoptical signals, and (2) telemetric communication circuitry that directsor manages signal transfer with the communication device 530. Suchsignal transfer may involve the transfer of measured or processedoptical monitoring signals, such that they may be analyzed by anexternal device (e.g., the SOMPD 500 or other device).

In some embodiments, optical monitoring operations may occur on aperiodic, intermittent, or specifically requested basis in order toconserve power. In some embodiments, the control and communication unit450, the SOMPD 500, and/or another device may determine one or moreneural stimulation parameters based upon detected and/or processedoptical signals, and possibly initiate, adjust, vary, query, interrupt,resume, or discontinue the application of neural stimulation signalsbased upon such detected or processed signals.

In certain embodiments, an ISOMC 400 may comprise, be based upon, and/orutilize one or more elements described in U.S. Pat. Nos. 5,520,190 and5,601,611, both of which are incorporated herein by reference in theirentireties.

Also shown in FIG. 4 is an OMA 460 according to an embodiment of theinvention. In one embodiment, the OMA 460 comprises a support member orstructure 464 configured to carry a set of optical emission elements 466and a set of optical detection elements 468. In various embodiments, anoptical emission element 466 and/or an optical detection element 468 maycomprise a set of optical fibers, possibly coupled to a lens ormicrolens; a wavelength filter; and/or another type of optical signalingelement (e.g., a MEMS device). The optical fibers may be coupled to theoptical I/O unit 430. In some embodiments, one or more portions of thesupport member or structure 464 may carry blocking, shielding, orfiltering elements (e.g., an optically opaque, absorbing, or blockingmaterial, coating, or layer) through which undesirable optical signals(e.g., optical signals originating external to the patient 10) that mayaffect optical monitoring operations.

The emission and detection elements 466, 468 may be positioned relativeto each other in a manner that facilitates the detection of opticalsignals that are scattered, reflected, and/or emitted (e.g., inassociation with fluorescence) by target tissues, which may resideproximate to and/or somewhat distant from a monitoring site. In arepresentative embodiment, particular emission and detection elements466, 468 may be separated from each other by approximately 0.5 cm toapproximately 5.0 cm, or approximately 1.5 cm to approximately 3.5 cm,or approximately 2.0 cm to 3.0 cm.

Depending upon embodiment details and/or particular target tissues underconsideration, optical signals detected by an OMA 460 may correspond orgenerally correspond to a target monitoring region 470. A targetmonitoring region 470 may be defined or approximately defined based upona type of optical signal path through tissue, which may correspond to amodified Beer-Lambert law. In a representative embodiment, an OMA 460may be implemented in a manner analogous to that described in U.S. Pat.No. 5,024,226, which is incorporated herein by reference in itsentirety.

FIG. 5 is a schematic illustration of an OMA 462 according to anotherembodiment of the invention. The OMA 462 of FIG. 5 comprises emissionelements 466 and detection elements 468 exhibiting a differentconfiguration than that shown in FIG. 4, and which may facilitatemonitoring corresponding to multiple target monitoring regions 470 a-h.

Also shown in FIG. 4 is a SOMA 480 according to an embodiment of theinvention. In one embodiment, the SOMA 480 comprises a support member orstructure 464 configured to carry a set of electrical contacts orelectrodes 122, a set of optical emission elements 466, and a set ofoptical detection elements 468. The electrodes 122 may be coupled to theelectrical signal I/O unit 420 by a set of lead wires 124, and theoptical emission and detection elements 466, 468 may be coupled to theoptical signal I/O unit 430. A target monitoring region 470 maycorrespond to tissue located between, beneath, and/or proximate to oneor more electrodes 122.

FIG. 6A is a schematic illustration of a SOMA 481 according to anotherembodiment of the invention. In one embodiment, the SOMA 481 comprises aset of electrodes 122, optical emission elements 466, and opticaldetection elements 468 configured in a manner that establishes orapproximately establishes one or more optical signal phase relationshipsbetween emission and detection elements 466, 468. For instance, a set ofoptical emission elements 466 and a set of optical detection elements468 may be positioned, organized, or arranged to form a phased opticalarray. Such phase relationships may be relevant to phase cancellationoptical signal analysis as described by Britton Chance et al., in “Anovel method for fast imaging of brain function, non-invasively, withlight,” Optics Express, Vol. 2, No. 10, 11 May 1998, p. 411-423, whichis incorporated herein by reference in its entirety.

FIG. 6B is a schematic illustration of a SOMA 482 according to anotherembodiment of the invention. In one embodiment, the SOMA 482 comprises aset of electrodes 122, optical emission elements 466, and opticaldetection elements 468 configured in a manner that establishes multipletarget monitoring regions 470. Many other types of support member,electrode, emission element, and/or detection element configurations arepossible in accordance with various embodiments of the presentinvention.

In some embodiments, a SOMA 480, 481, 482 may omit one or more opticaldetection elements 468, such that optical signals output by particularoptical emission elements 466 carried by the SOMA may be detected by oneor more optical signal detection devices that are external to thepatient (e.g., proximate to the patient's skull).

In certain embodiments, an ISOMC 400, an electrode assembly 120, an OMA460, and/or a SOMA 480 may be implemented using peg- or screw-typestructures, for example, in a manner that is identical and/or analogousto that described in U.S. Patent Application Publication No. US2005/0075680, incorporated herein by reference in its entirety, and U.S.Pat. No. 5,024,226.

FIG. 7 is a flow diagram of a process 600 for neural stimulation inassociation with optical monitoring according to an embodiment of theinvention. Process 600 may contain various process portions, particularaspects of which are described in detail hereafter.

Process portion 610 can include identifying one or more neuralstimulation and/or optical monitoring sites, and process portion 620 caninclude implanting a set of neural stimulation and possibly opticalmonitoring devices in a patient 10. Process portion 630 can includemonitoring optical signals in patient tissue, for example, within orrelative to one or more brain regions. Process portion 640 can includeapplying neural stimulation to the patient at one or more stimulationsites, in accordance with particular neural stimulation parameters.Process portion 650 can include monitoring optical signals in patienttissue, some of which may have been exposed to or affected by neuralstimulation signals.

Process portion 660 can include determining whether to adjust or varyneural stimulation, possibly based upon particular optical monitoringsignals and/or processed information associated therewith. In the eventthat neural stimulation is to be adjusted or modified, process portion670 can include determining an adjusted, modified, or updated set ofstimulation parameters, possibly based upon particular opticalmonitoring signals and/or processed information associated therewith.Process portion 640 may subsequently apply neural stimulation inaccordance with the updated stimulation parameters. Adjustment of neuralstimulation parameters populations may occur in a real-time,approximately real-time, or delayed manner. Process portion 680 caninclude determining whether to interrupt or discontinue neuralstimulation, in which case process portion 690 can include discontinuingneural stimulation and possibly optical monitoring operations.

In other embodiments, a process 600 may be directed toward neuralstimulation and/or chemical substance delivery in association withoptical monitoring. One or more of the previously described processportions may involve the application, variation, interruption, orcessation of chemical substance delivery based upon monitored opticalsignals and/or processed information generated from such signals, in amanner that may or may not depend upon the application of neuralstimulation to one or more target neural populations.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from theinvention. For example, certain aspects of the systems and methodsdescribed above may be automated or partially automated, and may beimplemented on computer systems and/or via computer-readable media. Inparticular embodiments, aspects of the stimulation site selectionprocedure and/or the evaluation procedure can be automated in such afashion. Further, in some embodiments, data obtained from a first neuralpopulation can be used to identify signal delivery parameters for asecond neural population of the same patient. In other embodiments, dataobtained from stimulating one type of neural population in one patientcan be used to at least influence the choice of signal deliveryparameters selected for a different type of neural population in adifferent patient. Aspects of the invention described in the context ofparticular embodiments may be combined or eliminated in otherembodiments. Although advantages associated with certain embodiments ofthe invention have been described in the context of those embodiments,other embodiments may also exhibit such advantages. Additionally, noneof the foregoing embodiments need necessarily exhibit such advantages tofall within the scope of the invention. Accordingly, the invention isnot limited except as by the appended claims.

1. An apparatus for treating a neural condition, comprising: a signaldelivery device configured to be implanted into a patient proximate to askull of the patient and positioned to apply electromagnetic signals toone or more target sites within the patient; an implantable opticalmonitoring assembly configured to monitor optical properties at one ormore optical monitoring sites within the patient; and a controllerconfigured to be implanted into the patient, the controller beingoperatively coupled to the signal delivery device and the opticalmonitoring assembly and programmed to control both the signal deliverydevice and the optical monitoring assembly, and wherein the controllerincludes a power source to power both the signal delivery device and theoptical monitoring assembly.
 2. The apparatus of claim 1 wherein thesignal delivery device comprises at least one electrode configured to beimplanted within the skull of the patient.
 3. The apparatus of claim 1wherein the signal delivery device comprises an electrode configured tobe positioned proximate to a cortical surface within the skull of thepatient.
 4. The apparatus of claim 1 wherein the optical monitoringassembly comprises: an implantable support member configured to beimplanted within the skull of the patient; one or more optical emissionelements carried by the support member; and one or more opticaldetection elements carried by the support member, wherein the one ormore optical emission elements and the one or more optical detectionelements are arranged relative to each other to detect optical signalsfrom the one or more optical monitoring sites.
 5. The apparatus of claim4 wherein the one or more optical detection elements and the one or moreoptical emission elements are arranged relative to each other to detectoptical signals that are scattered, reflected, and/or emitted by targettissues at the one or more optical monitoring sites.
 6. The apparatus ofclaim 4 wherein the one or more optical detection elements and the oneor more optical emission elements comprise at least one of an opticalfiber, a wavelength filter, and an optical signaling element.
 7. Theapparatus of claim 4 wherein the one or more optical detection elementsand the one or more optical emission elements are separated from eachother by approximately 0.5 cm to approximately 5.0 cm.
 8. The apparatusof claim 4 wherein the one or more optical detection elements and theone or more optical emission elements are separated from each other byapproximately 2.0 cm to approximately 3.0 cm.
 9. The apparatus of claim4 wherein a plurality of optical detection elements are arrangedequidistant or approximately equidistant from an optical emissionelement.
 10. The apparatus of claim 4 wherein a plurality of opticalemission elements are arranged equidistant or approximately equidistantfrom an optical detection element.
 11. The apparatus of claim 1 whereinthe optical monitoring assembly is a first optical monitoring assembly,and wherein the apparatus further comprises one or more additionaloptical monitoring assemblies positioned to monitor optical propertiesat the one or more optical monitoring sites.
 12. The apparatus of claim1 wherein the one or more target sites are first target sites and theoptical monitoring assembly is a first optical monitoring assembly, andwherein the apparatus further comprises: a second optical monitoringassembly positioned to at least one of (a) monitor optical properties atthe one or more optical monitoring sites, and (b) apply electromagneticsignals to the one or more second target sites.
 13. The apparatus ofclaim 12 wherein the second optical monitoring assembly comprises: animplantable second support member configured to be implanted within theskull of the patient; one or more electrodes carried by the secondsupport member and configured to receive and apply signals to the one ormore second target sites; one or more second optical emission elementscarried by the second support member; and one or more second opticaldetection elements carried by the second support member, wherein the oneor more second optical emission elements and the one or more secondoptical detection elements are arranged relative to each other to detectoptical signals from the one or more optical monitoring sites.
 14. Theapparatus of claim 12 wherein the first optical monitoring assembly andthe second optical monitoring assembly are implanted at different brainlocations of the patient.
 15. The apparatus of claim 12 wherein thefirst optical monitoring assembly is implanted proximate to a firstbrain location of the patient and the second optical monitoring assemblyis implanted proximate to a second brain location of the patient, andwherein the first optical monitoring assembly is positioned to detect ahemodynamic characteristic associated with neural activity in the firstbrain location, and the second optical monitoring assembly is positionedto detect a hemodynamic characteristic associated with neural activityin the second brain location.
 16. The apparatus of claim 1, furthercomprising an implantable support member, and wherein at least a portionof both the signal delivery device and the optical monitoring assemblyare carried by the support member.
 17. The apparatus of claim 1, furthercomprising a chemical delivery device positioned to release or apply oneor more chemical substances to one or more chemical delivery sites inthe patient.
 18. The apparatus of claim 17 wherein the chemical deliverydevice includes an implantable chemical delivery device
 19. Theapparatus of claim 1, further comprising: a communication device; and aprogramming device external to the patient and coupled to the controllervia the communication device, the programming device having instructionsto perform at least one of (a) directing the stimulation signals andoptical monitoring instructions and their issuance to the controller,(b) receiving, processing, and analyzing information received from thecontroller, (c) visually indicating signal delivery and stimulationinformation, and (d) visually indicating detected, estimated, ormeasured optical properties and physiologic or physiologic correlateproperties.
 20. A neural stimulation and optical monitoring system, thesystem comprising: an implantable electrode positioned to transmitsignals to a target neural population of a patient; an opticalmonitoring assembly positioned to apply optical signals to and detectoptical signals scattered within or reflected by tissue of the patientat one or more optical monitoring sites proximate to a skull of thepatient; and an implantable controller operatively coupled to theelectrode and the optical monitoring assembly, the controller beingprogrammed with instructions to manage (a) the application of signals tothe target neural population, and (b) the detection and processing ofoptical signals at the one or more optical monitoring sites. 21-54.(canceled)